Altkireii, a town of the new German department of Upper Alsace, on the 111, 16 m. E. of Belfort, France, and 70 m. S. of Strasburg; pop. about o,200. It is a manufacturing town of some importance, and contains a fine modern church and a ruined castle, which in former times was occupied by the Austrian archdukes in their visits to Alsace. It was founded in the 12th century, and belonged to the counts of Pfirt (Ferrette). The German authorities have selected Altkirch as the town to be fortified as a counter-fortress to Belfort.